首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The Caribbean Islands are one of the ten insular biodiversity hotspots that are defined based on endemicity, massive habitat loss and vulnerability to extinction. Asteraceae genera endemic to islands have provided well known examples of plant radiation worldwide and illustrate the importance of these insular systems for evolutionary and conservation studies. A review of known patterns of taxonomic diversity and molecular cladistics is provided for Asteraceae genera and species endemic in the Caribbean Island biodiversity hotspot. We found that when compared with other island systems worldwide the Caribbean Islands have the highest number of endemic genera (41), have endemic genera in the highest number of tribes, and harbor the only Asteraceae tribe endemic to an island system, the Feddeeae which is restricted to Cuba. These unique patterns identify the Caribbean Islands as the most important insular area of endemism for this major plant family. Molecular cladistic studies are limited to only seven species in seven endemic genera and six endemic species in five non-endemic genera. These few studies are however relevant as: (1) they confirm the tribal status of the Feddeeae, (2) suggest colonization events from the highlands of Cuba toward low elevation and geologically recent areas of the Bahamas and South Florida, (3) provide evidence for biogeographical links to remote regions of the Pacific Basin, and (4) identify sister relationships with continental taxa, mostly from North America.
Resumen  Las Islas del Caribe son uno de los diez “punto calientes” insulares de biodiversidad, los cuales vienen definidos por sus niveles de endemicidad, masiva pérdida de habitat y vulnerabilidad y extinción. Asteráceas endémicas de islas han proporcionado ejemplos muy bien conocidos de radiación vegetal a nivel mundial, éstos ilustran la importancia de los sistemas insulares en estudios evolutivos y de conservación. Se presenta una revisión de las pautas de diversidad taxonómica y de cladismo molecular en Asteráceas de las Islas del Caribe. Hemos encontrado que comparadas con otros sistemas insulares, las Islas del Caribe tienen el mayor número de géneros endémicos (41), tienen géneros endémicos en el mayor número de tribus y poseen la única tribu de la familia endémica en islas, Feddeeae es endémica de Cuba. Estas pautas de diversidad exclusivas de las Islas del Caribe hacen que éstas sean el área de endemismos insulares más importante para las Asteráceas. Estudios de cladismo molecular se limitan solamente a siete especies en siete géneros endémicos y a seis especies en cinco géneros no endémicos. Este reducido número de estudios son de todas formas relevantes debido a que: (1) confirman el estatus a nivel de tribu de Feddeeae, (2) sugieren una ruta de colonización desde zonas altas de Cuba hacia áreas de baja elevación de las Bahamas y el sur de la Florida, (3) proporcionan evidencia de conexiones biogeográficas con regions remotas del Océano Pacífico, y (4) identifican relaciones de hermandad con táxones continentales, principalmente de América del Norte.
  相似文献   

2.
Trans-Himalayan mountains, owing to harsh climatic conditions and a short growing season support low vegetation cover (<20%), yet it is known to harbour a unique assemblage of flora and fauna which have not been systematically inventoried and documented so far. This paper deals with spatial and non-spatial information on landscape units, vegetation characteristics and plant species diversity of Nubra Valley in Ladakh, India. Based on digital – visual (on screen) interpretation of remote sensing data coupled with knowledge-based classification we delineated 19 cover classes (11 vegetation types and 8 non-vegetation categories). The vascular plants (angiosperms and gymnosperms) were systematically collected using stratified random sampling of different landscape/vegetation to characterize plant communities and assess the distribution patterns of species. The study reveals that nearly 78–80% of plant species in Nubra are restricted to the valley bottoms. In all, 414 species of vascular plants were recorded from the study area. These belongs to 56 families and 202 genera. Of these, 102 species were reported to be used in traditional system of medicine by Amchis over 80 species are largely associated with cultivated fields and human habitation. As many as 49 species were cultivated which include several varieties of crop plants especially those of barley and buckwheat. Aspects of bioprospecting and conservation of valuable species have been discussed.  相似文献   

3.
在对植物调查研究的基础上,对长江中游(湖北、湖南为主)的植物区系、植被、生物多样性保护及保护对策进行了系统的论述。根据两省土著种子植物名录统计,本区共有202科1476属7037种(包括种下等级),其中裸子植物7科30属64种;被子植物196科1445属6973种。以鄂湘为代表的华中区分布类型复杂、物种丰富、起源古老,而且特有的科、属、种多,特有度高。北温带木本植物属高度集中,体现了长江中游具有古第三纪.泛北极植物区系的代表性。拥有众多的东亚特有属、东亚.北美间断分布属和中国特有属,它们既是本地植物区系的特色,也代表了中国植物区系的核心。本地中山以亮叶水青冈(Fagus lucida)为主的阔叶林系第三纪.泛北中生落叶阔叶林的后裔。在植被区划上,本区属于常绿阔叶林区域,包括北亚热带常绿阔叶.落叶阔叶混交林地带及中亚热带常绿阔叶林两个植被地带。后者分为北部典型常绿阔叶林亚地带,南部含华南植物区系成分的常绿阔叶林亚地带。本区主要的自然植被类型(以原生类型为主)有171个类型(相当于群系formations)。从生物多样性保护的三个层次上(物种、群落、景观)对保护现状、特点、保护方针和策略等进行了探讨并提出了建议。  相似文献   

4.
蚌科动物是世界上最濒危的动物类群之一,对该类动物的生物多样性保护是非常有意义的。微卫星DNA标记的发展和利用将有利于蚌科动物的遗传多样性保护。从微卫星标记的特点、研究方法、研究结果等方面综述了微卫星DNA标记在蚌科动物中的研究进展,并展望了中国蚌科微卫星DNA标记的研究方向。  相似文献   

5.
湖北后河自然保护区拥有丰富的生物多样性,为中国生物多样性三大关键地区之一的川东-湘鄂西关键地区的重要组成部分。但所处的贫困山区少数民族县长期以来以森工产业为其县域经济的主要支柱,长期的木材采伐和狩猎习俗曾对该保护区的生物多样性带来了严重破坏。自然保护区的建立使其生物多样性逐渐得到了有效保护,特别是升为国家级自然保护区后,生物多样性保护进入了一个新阶段。但该保护区的生物多样性依然面临多种威胁,保护区自身科学研究力量的薄弱和保护区面积相对较小,限制着该区域生物多样性的进一步研究和保护。进一步扩充保护区面积、引进科研力量并提升自身人员科研素质、协调并增强区内外社区共管是该区生物多样性得到进一步保护和恢复的当务之急。  相似文献   

6.
生物多样性的生态系统功能   总被引:10,自引:0,他引:10  
本文从以下几个方面综述了生物多样性对生态系统功能和作用的影响 :第一 ,几个关于物种在生态系统中的不同地位和生物多样性如何影响生态系统功能的假说 ;第二 ,生物多样性与生态系统的稳定性 ;第三 ,生物多样性如何影响生态系统的生产力 ;第四 ,生物多样性对生态系统可持续性的影响。此外还提出了几个需要继续探讨和关注的问题  相似文献   

7.
民族植物学是一门研究人与植物相互关系的学科,用于了解世界各地人与植物的相互关系,对于寻找保护植物的最好方法至关重要,这一科学领域在许多国家被应用于有关植物的传统知识调查记载,大量地方性植物区系中的有用植物编目已经完成.在过去一百年中,从民族植物学调查获得的有关植物的地方性知识,对于药物和农业发展,以及植物新产品开发作出了巨大贡献.自从20世纪60年代以来,科学界更为关注全球环境变化的重要性,现代环境变化的速度是人类历史上从来没有过的.自然资源正以惊人的速度消失,威胁到大量物种以至最终灭绝.面对这一危机,民族植物学研究面临的紧迫任务,不仅是作为一种科学工具应对环境的退化,而且由于它的巨大潜力,能为植物资源可持续利用和农村扶贫作出重要贡献.民族植物学研究对现代发展的贡献是多方面的,其中包括:构建传统植物学信息库为保护和发展服务;管理景观系统为保护工作提供各种形式的帮助;加强社区参与农村发展的活力.本文围绕民族植物学在生物多样性保护和现代农村发展中的作用,生物多样性保护和可持续利用面临的挑战,以及生物与文化途径在利用和保护生物多样性中的作用等进行了探讨.  相似文献   

8.
Throughout the world, plant diversity is being reduced rapidly by the extinction of species and of local differentiated populations. In presenting possible solutions to this very serious problem Ⅰ will first briefly describe the factors that have led to the development of China's wealth of biodivenity; then examine the causes of extinction,with an emphasis on the situation in China; and conclude with recommendations on how to most effectively conserve plants in this huge and botanically diverse country.  相似文献   

9.
Throughout the world,plant diversity is being reduced rapidly by the extinction of species and of local differentiated populations.In presenting possible solutions to this very serious problem I will first briefly describe the factors that have led to the development of China’s wealth of biodiversity;then examine the causes of extinction,with an emphasis on the situation in China;and conclude with recommendations on how to most effectively conserve plants in this huge and botanically diverse country.  相似文献   

10.
Diversity and extinction in the Cenozoic history of Caribbean reefs   总被引:5,自引:0,他引:5  
Occurrences of reef corals are examined at Caribbean fossil localities to determine how biodiversity has changed within the region over the past 50 million years. Analyses of 294 species (66 genera) at 58 fossil localities show that Caribbean generic diversity rose to 44 between 50–22 Ma, ranged from 32–39 between 22–2 Ma, and dropped to 25 afterwards. Regional species diversity was high at 40–36 Ma, 28–22 Ma, and 5–2 Ma. Origination rates were elevated throughout each high diversity interval, but extinction was concentrated near the end of each interval. Regional highs of origination and extinction, therefore, differed in timing and duration, causing the observed regional diversity increases during the three remarkably long intervals of turnover. Highs of generic origination decreased in magnitude as immigration from the Mediterranean ceased, but speciation highs increased in association with emergence of the Central American isthmus. Peaks of extinction coincided with regional changes in climate and oceanic circulation. Maximum species diversities within assemblages increased to 40–60 between 50–36 Ma, and have remained relatively constant ever since. Assemblage compositions differed among localities having similar ages and environments, suggesting that the timing and pattern of turnover varied across the region. Stable diversities but variable compositions within assemblages suggest that dispersal and recruitment influenced the pattern of faunal change during turnover. Accepted: 22 August 1999  相似文献   

11.
Biodiversity and wetlands   总被引:2,自引:0,他引:2  
The implications of the Biodiversity Convention of the UNCED Conference in Rio are discussed in terms of the obligations of participating states. The importance of biodiversity is outlined with special reference to wetland ecosystems. The values of wetlands and wetland biodiversity are discussed and a possible classification strategy for their conservation and wise use is suggested.Corresponding Editor: R.E. Turner  相似文献   

12.
Human domination of the Earth has resulted in dramatic changes to global and local patterns of biodiversity. Biodiversity is critical to human sustainability because it drives the ecosystem services that provide the core of our life-support system. As we, the human species, are the primary factor leading to the decline in biodiversity, we need detailed information about the biodiversity and species composition of specific locations in order to understand how different species contribute to ecosystem services and how humans can sustainably conserve and manage biodiversity. Taxonomy and ecology, two fundamental sciences that generate the knowledge about biodiversity, are associated with a number of limitations that prevent them from providing the information needed to fully understand the relevance of biodiversity in its entirety for human sustainability: (1) biodiversity conservation strategies that tend to be overly focused on research and policy on a global scale with little impact on local biodiversity; (2) the small knowledge base of extant global biodiversity; (3) a lack of much-needed site-specific data on the species composition of communities in human-dominated landscapes, which hinders ecosystem management and biodiversity conservation; (4) biodiversity studies with a lack of taxonomic precision; (5) a lack of taxonomic expertise and trained taxonomists; (6) a taxonomic bottleneck in biodiversity inventory and assessment; and (7) neglect of taxonomic resources and a lack of taxonomic service infrastructure for biodiversity science. These limitations are directly related to contemporary trends in research, conservation strategies, environmental stewardship, environmental education, sustainable development, and local site-specific conservation. Today’s biological knowledge is built on the known global biodiversity, which represents barely 20% of what is currently extant (commonly accepted estimate of 10 million species) on planet Earth. Much remains unexplored and unknown, particularly in hotspots regions of Africa, South Eastern Asia, and South and Central America, including many developing or underdeveloped countries, where localized biodiversity is scarcely studied or described. "Backyard biodiversity", defined as local biodiversity near human habitation, refers to the natural resources and capital for ecosystem services at the grassroots level, which urgently needs to be explored, documented, and conserved as it is the backbone of sustainable economic development in these countries. Beginning with early identification and documentation of local flora and fauna, taxonomy has documented global biodiversity and natural history based on the collection of "backyard biodiversity" specimens worldwide. However, this branch of science suffered a continuous decline in the latter half of the twentieth century, and has now reached a point of potential demise. At present there are very few professional taxonomists and trained local parataxonomists worldwide, while the need for, and demands on, taxonomic services by conservation and resource management communities are rapidly increasing. Systematic collections, the material basis of biodiversity information, have been neglected and abandoned, particularly at institutions of higher learning. Considering the rapid increase in the human population and urbanization, human sustainability requires new conceptual and practical approaches to refocusing and energizing the study of the biodiversity that is the core of natural resources for sustainable development and biotic capital for sustaining our life-support system. In this paper we aim to document and extrapolate the essence of biodiversity, discuss the state and nature of taxonomic demise, the trends of recent biodiversity studies, and suggest reasonable approaches to a biodiversity science to facilitate the expansion of global biodiversity knowledge and to create useful data on backyard biodiversity worldwide towards human sustainability.  相似文献   

13.
Resolving the conflicts between biodiversity conservation and socioeconomic development is a global pursuit for the long-run prospects of the human species. Based on Wenchuan County, a typical county in southwestern China, a group of 20 indicators quantifying regional biodiversity and socioeconomic development was established to classify and evaluate the county area spatially. A fuzzy c-means clustering (FCM) algorithm was used as the classification method. Three indices including BD, DL and DR characterizing the value of biodiversity, the level and rate of socioeconomic development of the delineated regions were formulated. The results indicated that Wenchuan County was optimally classified into 4 types of regions (region I to IV). The area percentages of the regions vary widely from 4.3 to 65.7%. The sequences of the regions on biodiversity, socioeconomic development level, and socioeconomic development rate were, respectively, IV > II > III > I, I > III > II > IV and III >I >II >IV. The spatial strategy on coordinating biodiversity conservation and regional development is to develop mainly from the east(I, II, III) and to conserve mainly in the west(IV). Eco-industry, such as eco-tourism and eco-agriculture, need to be emphasized in the process of regional development. The quantitative methods used here may have a wide applicability.  相似文献   

14.
尤溪县生物多样性保护优先地区分析   总被引:7,自引:2,他引:7  
李迪强  林英华  陆军 《生态学报》2002,22(8):1315-1322
选择人类活动频繁的常绿阔叶林林区具有代表性的福建尤溪县进行了生物多样性保护的优先性分析。在多次实地调查基础上,利用野生动物野外实地样带调查数据,已有的珍稀淑危鸟,兽和植物物种的分布资料,同时结合利用地理信息系统软件ARC/INFO数字化1:10万林相图和1:5万地形图,建立了基于GIS的尤溪县生物多样性信息系统,然后根据物种多样性,珍稀濒危物种保护和生态系统保护目标,确立了保护优先性分析原则,即珍稀濒危物种尽可能包含在保护区和保护小区内,同时在优先保护区尽可能包含更多的其它物种,用最新的森林分布图及调查物种分布与生境关系,生态系统在保护物种与生态系统功能等方面的作用等,提出了生态系统的保护优先地区,将提出保护优先地区与已建保护小区和保护点分布图进行叠加分析表明,保护小区和保护点的方法是保护珍稀濒危物种的有效方法,但是需要考虑保护小区之间的联系,在对大型哺乳动物保护时需要建立面积较大的自然保护区,最后,提出了建立自然保护区规划。  相似文献   

15.
Coccothrinax jimenezii M.M. Mejía & R.G. García is a Critically Endangered palm species restricted to Haiti (one population near the city of Gonaïves with 43 individuals) and the Dominican Republic (one population on the shores of Lago Enriquillo with 18 individuals). The species faces two major conservation challenges: (1) water level rise in the hypersaline Lago Enriquillo and (2) overexploitation of leaves for making brooms in Haiti. Six SSR microsatellite loci were used to access levels of genetic variation and the genetic structure of these two populations. Only the Gonaïves site had loci that deviated from Hardy–Weinberg Equilibrium (2 loci). Both populations exhibited a relatively large number of private alleles (13 in Lago Enriquillo and 14 in Gonaïves) and did not show evidence of genetic bottlenecks. Inbreeding coefficients were much larger in Gonaïves (Fis = 0.232) than in Lago Enriquillo (Fis = 0.093). We detected high genetic differentiation among these sites (Fst = 0.497) suggesting that additional taxonomic studies are needed to determine if individuals from these two sites should be recognized as belonging to two different taxa. Because of taxonomic uncertainties we recommend not to translocate individuals between sites in future conservation activities involving this species.  相似文献   

16.
With diversification of field type among households in same eco-environment and social situation, even in the same ecosystem, merging household socio-economics with biodiversity initiative values to determine incentives and optimum strategy of on-farm conservation of biodiversity. Botany survey of agroecosystems at landscape level in Daka and Baka, Xishuangbanna, Yunnan, China, as well as household differentiation of biodiversity in agroecosystem and on-farm conservation strategy merging household socio-economic characters were studied. There were 73 families 179 species distributed in 0.1 ha of different agroecosystems in Daka, and 70 families 166 species distributed in 0.08 ha different agroecosystems of Baka respectively. The cosmopolitan families, such as Gramineae and Compositae decreased the percentage of tropical families and subtropical families. Botany survey among 12 random selected households from Daka in 46 sampling plots of different agroecosystems showed significant differentiation of the species richness indices of natural biodiversity and agrobiodiversity as there were differences of cognition and utilization of plant species besides management practices among households. Dengrogram using the Ward method of hierarchical cluster analysis based on annual questionnaire interview of 60% household from 1998 to 2001 in Daka showed disparity among different households’ socio-economics which underpins management diversity. There were significant correlation coefficients between household socio-economics and species richness indices of different agroecosystems. Fallow size had significant positive correlation coefficients with species richness index of rubber plantation. By contraries, production input had negative correlation coefficients with species richness index of upland rice field. Meanwhile, cereal crop income had significant positive correlation coefficient with agro-species richness index of rubber plantation. By contraries, other income such as off-farm income had negative correlation coefficients with agro-species richness index of rubber plantation. Innovations of the expert farmer on agrobiodiversity on farm conservation were admiration.  相似文献   

17.
Caribbean archaeologists have tended to focus exclusively on the prehistory of the largest islands, perhaps because large islands are believed to provide the landmass necessary to support long-term population growth and cultural development. Yet, as research here and elsewhere, e.g., the Pacific, is showing, small islands provided access to resources and landscapes that were not always readily available on the larger islands. Small islands often have superior terrestrial and, especially, marine resources; isolated ritual spaces; and more easily defended locations; although they are susceptible to more rapid overexploitation. This paper examines in detail human needs with regard to island size, demonstrating that small islands were crucial in the development of pre-Columbian Caribbean societies. Four case studies are presented to illustrate that small islands often were preferred over large islands throughout the Caribbean archipelagoes. Finally, these studies show that the prehistoric exploitation and overexploitation of small islands can provide significant insights for establishing baselines that can be used for modern management and conservation efforts.
William F. KeeganEmail:
  相似文献   

18.
China is among the world's richest countries in terms of plant biodiversity. Besides the abundant flora, containing some 33,000 vascular plants (30,000 angiosperms, 250 gymnosperms, and 2600 pteridophytes), there is extraordinary ecosystem diversity, as well as a large pool of both wild and cultivated germplasms. China is also considered one of the main centers of origin and diversification for seed plants on Earth, and is especially profuse in phylogenetically primitive taxa and/or paleoendemics due to the refuge role glaciation played during the Quaternary period. The collision with the Indian subcontinent significantly enriched Chinese flora and led to the formation of many neoendemisms. However, flora distribution remains uneven, and some local floristic hotspots are found across China, such as Yunnan, Sichuan and Taiwan. Unfortunately, this biodiversity faces enormous threats, which have increased substantially over the last 50 years. The combined effects of habitat destruction and/or fragmentation, environmental contamination, over-exploitation of natural resources, and to a lesser extent, introduction of exotic species, have caused irreparable damage to China's plant biodiversity. Burgeoning economic and population growth have also contributed to this deterioration. It is believed that up to 5000 flora species are currently endangered in China, with some taxa having already become extinct. Although in recent years government authorities have made some efforts to preserve biodiversity, much work remains to be done. While China has established an extensive network of nature reserves and protected areas, encompassing more than 16% of the total land area, insufficient budgetary and staffing commitments are common limitations in their management structures. Ex-situ conservation is also deficient, primarily because the botanical gardens are not representative of several local floras, nor are they often of adequate size or representative of endangered species. The lack of effective and efficient environmental legislation and education are also problems that continue to accelerate the loss of plant biodiversity in China.  相似文献   

19.
20.
As the capital of China, Beijing has experienced extensive urbanization in the past two decades. To explore the effect of urbanization on plant diversity, we investigated the vascular plant diversity of the whole Beijing Municipality in three different functional (urban, suburban and exurban) regions. For its geo-diversity, Beijing has a rather abundant vascular plant diversity (2,276 species), including 207 species of conservation concern such as endemic, threatened and protected species. The exurban region had not only the highest species diversity (1,998 species), but also the most species of conservation concern (194 species). Urban region possessed the maximum alien species in terms of both absolute number and proportional representation, while the suburban region had the least species diversity (1,026 species). Some problems, such as wetland shrink and biological invasions, were common in the whole Beijing Municipality. However, primary threats to biodiversity differed in the three functional regions. The urban and suburban regions mainly suffered from habitat loss and fragmentation due to urban sprawl, while the exurban region faced serious ecosystem degradation from increasing disturbance from both local and urban people. Based on our investigation, we put forward conservation strategies for the three regions: improving the structure and ecological function of green spaces in urban region, preserving as much remnant natural habitats in the suburban region, and restricting the rural tourism and establishing a biosphere reserve in the exurban region. In addition, improving public education and orientating that more to social aspects of conservation practice is strongly recommended.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号